Ring of evasion
A ring that makes its wearer either more or less capable of avoiding attacks, depending on its degree of enchantment. |
A +4 or -4 ring of evasion affects the evasion of its wearer. If the enchantment is negative, the ring is usually cursed. Even if you've identified rings of evasion in general, you won't know whether the enchantment is positive or negative until after you've put it on.
Desirability
All characters can benefit from more EV, but sacrificing a ring slot for it may or may not be a good idea depending on your other resistances. Unlike most amulets, rings take effect immediately, so you can quickly switch between them at need. A ring of evasion is more likely to be useful for characters with low EV; mechanically, there is a much greater difference between 5 and 9 compared to 25 and 29.
History
Prior to 0.25, enchantments were random values between 1 and 6 (positive and negative).